Sudoku is a logic puzzle game, players goal is to populate the grid with numbers, each row, column and inner 3X3 grid should contain 1 - 9 number digit only, no repeated number is allowed.
There are three tools erase, edit and notes, tap erase button to remove an entered number or note. Tap edit/pencil button to activate manual note mode, you can put 9 (1 - 9) notes in a cell, tap notes button to put automatic notes.